Just to clarify, I was just talking about changing:

127::64.151.65.200:80:::
to
127::64.151.65.200:8000:::

has the same effect on my TiVo (failing part way through preparing downloaded data). If you never changed it in the tclient.conf I doubt it's the same problem. If you are stuck maybe it's worth doing a EPG perge anyway following MrGadget's instructions. Keep in mind this wipes out your Season Passes and Wishlists too.